Salinas River Channel
Salinas River Channel Maintenance Program
Monterey County Farm Bureau is very concerned with the potential of a flood event occuring during the expected El NIno event coming this winter. Damages could be far reaching and cost our economy millions of dollars and damage our environment for many years, possibly a decade or more.
The Salinas River provides our Valley with a unique water source for both farm and urban uses. This river has been artificially modified with flow rates maintained by releases from the upstream reservoirs during dry months each year (generally May through October). This year-round water source provides ecological benefits for a number of constituents throughout our Valley, as well as sustaining our local communities.
One of the more unique aspects of this river is that most of the land is privately held. This has provided land owners with the ability to maintain the dikes and levees used to control the flow of the river through their properties. After the flood events of 1995 and 1998, maintenance of the river channel was done under the supervision of permitting agencies; this maintenance not only controlled the rate of flow of the river and its path, but also decreased the amount of invasive shrubs and sediment that find a home in the river channel.
The maintenance of the Salinas River channel was halted eight years ago when the Central Coast Regional Water Quality Control Board denied the renew of their permit for the maintenance program, and instead ordered Monterey County Water Resources to prepare a costly Environmental Impact Report (EIR) on the river channel watershed. After over three years of delay, the Environmental Impact Report for the Salians River Stream Maintenance Program was certified by the Board of Supervisors in July 2014.
The Salinas Californian ran an article on December 9, 2013 that discussed the possibility of flooding along the Salinas River and some of the challenges in resolving channel maintenance issues.
In early October 2014, MCWRA received approvals from all resource agencies to move forward with a demonstration project in the unconstrained channel area between Gonzales and Chualar. Approximately 11 miles of the secondary river channel received vegetation management and sediment 'smoothing.' The aim is to improve capacity flow of the overall channel should additional water flows occur. See images of this project here. This demonstration project could become a model for other reaches of the unconstrained channel; a new project will need to be developed to manage the river channel in the constrained reaches, from Chualar north to the Monterey Bay coast.
Work is continuing on secruing permits for the remaining 82 miles of river channel maintenance; this involves extensive flood modeling of the river channel and vegetation mapping. Applications for permits are expected to be filed late this fall, with approval in August 2016. Maintenance work in the channel can then commence in October 2016.
Flooding potential enhanced by vegetation and sediment
The 2014/2015 rainy season ended in a whimper, without substantial rainfall to refill our depleted reservoirs. We are in desperate need of rain this fall and next winter for the Salinas Valley community and having Mother Nature refill our reservoirs is top of the list. For the last two years, we found ourselves without year-round releases of water into the Salinas River, affecting groundwater recharge, habitat and fish, and our local environment.
But this all comes with another consequence: while we need rainfall this next year, too much at one time could cause flooding along the river corridor. Similar to what we saw in 1995, 1998, and again in 2011, the river channel may overflow its banks and undermine levies due to the increased capacity of runoff. The EIR estimates flow capacity of the river channel at 39,000 cubic feet / second, far lower than the flood levels of 1995 and 1998.
Now why would rainfall in any sizable amount be the cause of a risk for flooding? Anyone who drives across the river bridges anywhere along the valley can see that the river is barely visible due to the proliferation of vegetation in the streambed. Some of this vegetation is native to our area, but a large amount of the vegetation is invasive, meaning it doesn’t belong in our streambed. With the year-round releases of water from the two reservoirs we have created a habitat where vegetation can rapidly grow due to continuous moisture, particularly for fast-growing invasive plants.
How did we get to this point, where the streambed is so choked with vegetation and sediment that water velocity is at 10% the rate of eight years ago, and nearly 16,000 additional acre feet of water are consumed each year by this vegetation? Simple answer: five years ago two of the state and federal agencies that issue permits for streambed maintenance withheld their renewal of these permits. Landowners along the river have been performing streambed maintenance within the channel since the 1995 flood with the aid of these permits; without the renewal of these permits, all channel maintenance was halted and vegetation and sediment began building up quickly.
We now have a streambed choked with sand and plants, many of which are now stressed or dying due to the drought, and landowners are prevented from maintaining and protecting their own land (yes, landowners here actually own the riverbed itself, unlike other rivers in California). Trash removal from the river channel cannot be accomplished without the violating envirnmental restrictions for access and accidental removal of vegetation. What should have been a continuous operation performed each year by the landowners and farm operators has now become a river impeded by its own sediment and vegetation.
Circumstances are far different now for farmland that becomes flooded; due to food safety requirements, production cannot resume until extensive tests are completed to ensure that no pathogens remain in the soil or water supply. This will fallow farmland for considerable periods of time, meaning many months.
And it’s not just landowners along the river who will lose property (read: topsoil) if we have a flood. Municipalities along the valley have facilities for waste water treatment, domestic water systems, and parks along the river that are in jeopardy of being washed away if a flood event does occur. If the river does breach its streambed in one area, water could travel miles downriver before it were to rejoin the main river flow due to its meandering nature. Streambed course alterations would be permanent and the loss of other infrastructure, such as bridges, is quite possible, similar to what we experienced in the 1995 flood.
Do we really want to wash our topsoil, reclamation pond water, and other infrastructure into the Marine Sanctuary due to a flood that can be avoided, simply if we maintain the streambed properly?
Farmers and ranchers were maintaining the streambed, at their own expense, and are willing to do so once again, for the greater good of our collective community. What is needed to restart this process? First, issue permits from all the agencies involved to get the exotic vegetation under control, as well as the accumulated sediment. The Resource Conservation District of Monterey County received their permit for exotic vegetation removal the past two summers and have worked on removing exotic vegetation in the river channel reach between King City and Gonzales. Second, let’s all realize that we need to protect our natural resources as working environments, and maintaining our river channel will prevent washing our topsoil into the Marine Sanctuary, causing untold effects on aquatic life and water quality in our bay. We must balance our environmental needs in a more holistic manner.
We are facing dire consequences if the expected flood event does occur here … one that will take years to recover from, both physically and economically. Every citizen, municipality, and elected official in Monterey County should be voicing their support for a streambed management program that effectively reduces our risk for flooding to the maximum extent possible. Our environment is important, but our economy and infrastructure should be equally as important.